Editing Qualitative inorganic analysis (section)

=== 5th analytical group of cations ===
Ions in 5th analytical group of cations form [[carbonate]]s that are insoluble in water. The reagent usually used is [[ammonium carbonate|(NH<sub>4</sub>)<sub>2</sub>CO<sub>3</sub>]] (at around 0.2 M), with a neutral or slightly basic pH. All the cations in the previous groups are separated beforehand, since many of them also form insoluble carbonates.

The most important ions in the 5th group are [[barium|Ba<sup>2+</sup>]], [[calcium|Ca<sup>2+</sup>]], and [[strontium|Sr<sup>2+</sup>]]. After separation, the easiest way to distinguish between these ions is by testing flame colour: barium gives a yellow-green flame, calcium gives brick red, and strontium, crimson red.